US8064428B2ExpiredUtilityPatentIndex 79
Method and apparatus for ordering retransmissions in an NxM MIMO system
Est. expiryAug 12, 2025(expired)· nominal 20-yr term from priority
H04B 7/0623H04L 1/0668H04L 1/0009H04B 7/0848H04B 7/0697H04B 7/0669H04L 1/1867H04L 1/1819H04L 1/0625H04L 1/1845H04L 1/1607H04L 1/1812
79
PatentIndex Score
11
Cited by
11
References
20
Claims
Abstract
A method is provided for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N×M antennas. A transmitter splits a coded data stream into N sub-packets, and transmits the N sub-packets to a receiver via N transmission antennas. The receiver removes interferences of the N sub-packets received via M reception antennas, and independently decodes the interference-removed sub-packets. The receiver transmits an acknowledgement (ACK) or a negative acknowledgement (NACK) to the transmitter based on errors included in the decoded sub-packets. Upon receipt of the NACK, the transmitter retransmits to the receiver a sub-packet retransmission using ordering based on an Alamouti space-time coding scheme.
Claims
exact text as granted — not AI-modified1. A method for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N×M antennas, the method comprising:
splitting, at a transmitter, a coded data stream into N sub-packets, and transmitting the N sub-packets to a receiver via N transmission antennas;
removing, at the receiver, interferences of the N sub-packets received via M reception antennas, and independently decoding the interference-removed sub packets;
transmitting, at the receiver to the transmitter, one of an acknowledgement (ACK) and a negative acknowledgement (NACK) depending on errors included in the decoded sub-packets; and
upon receipt of the NACK, retransmitting to the receiver, at the transmitter, a sub-packet retransmission based on an Alamouti space-time coding scheme in descending order of signal to noise ratios (SNRs).
2. The method of claim 1 , further comprising canceling interference and decoding by combining, at the receiver, the retransmitted sub-packet with the previous defective sub-packet on a symbol level.
3. The method of claim 1 , wherein the interference removing is achieved by Minimum Mean Square Examination (MMSE) or Zero Forcing (ZF).
4. The method of claim 1 , wherein a signal-to-noise ratio (SNR) criterion of each reception antenna, determined at the receiver at every retransmission, is used for selection of the retransmission ordering.
5. The method of claim 4 , wherein a highest SNR of each reception antenna maximizes a determinant that derives a channel matrix after each retransmission.
6. The method of claim 5 , wherein the channel matrix is adaptively changed by checking a channel every time there is a need for retransmission.
7. The method of claim 5 , wherein the channel matrix is expressed as
H
M
×
N
=
(
h
11
h
12
⋯
h
1
N
h
21
h
22
⋮
⋮
⋱
⋮
h
M
1
…
…
h
M
N
)
.
8. A transmission apparatus for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N×M antennas, the apparatus comprising:
a channel encoder for encoding input information bits based on a coding scheme, and generating coded packets having a specific length;
a spatial demultiplexer for encoding the coded packets based on a space-time coding scheme, and parallel-converting the encoded packets into N sub-blocks;
symbol mappers for modulating the N sub-blocks output from the spatial demultiplexer into modulation symbol streams using a modulation scheme, mapping the symbol streams to times and frequencies based on a pilot sub-carrier position set pattern, and outputting the mapping results to associated transmission antennas; and
N transmission antennas for separately transmitting N sub-packets split from each of the coded symbol streams,
wherein, upon receipt of a negative acknowledgement (NACK) due to errors included in the transmitted sub-packets, the transmission apparatus arranges columns of a retransmission matrix based on an Alamouti space-time coding scheme in a descending order of signal to noise ratios (SNRs), and retransmits a retransmission sub-packet according to the arranged columns to a reception apparatus.
9. The transmission apparatus of claim 8 , wherein a signal-to-noise ratio (SNR) criterion of each reception antenna, determined at the receiver at every retransmission, is used for selection of the retransmission ordering.
10. The transmission apparatus of claim 9 , wherein a highest SNR of each reception antenna maximizes a determinant that derives a channel matrix after each retransmission.
11. The transmission apparatus of claim 10 , wherein the channel matrix is adaptively changed by checking a channel every time there is a need for retransmission.
12. The transmission apparatus of claim 10 , wherein the channel matrix is expressed as
H
MxN
=
(
h
11
h
12
⋯
h
1
N
h
21
h
22
⋮
⋮
⋱
⋮
h
M
1
⋯
⋯
h
MN
)
.
13. A reception apparatus for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N×M antennas, the apparatus comprising:
M reception antennas for separately receiving N sub-packets split from a coded symbol stream;
a pre-combiner for combining a sub-packet retransmitted according to retransmission ordering, with a previous defective sub-packet on a symbol level; and
a detector for removing interference of a signal received from the pre-combiner, splitting the interference-removed signal into N transmission data sub-packets after said removing, and outputting independently decoded sub-packets;
wherein the reception apparatus transmits one of an acknowledgement (ACK) and a negative acknowledgement (NACK) to a transmission apparatus depending on errors included in the decoded sub-packets and receives from the transmission apparatus the retransmitted sub-packet in response to the NACK transmitted by the reception apparatus, and the retransmission ordering comprises arranging columns of a retransmission matrix based on an Alamouti space-time coding scheme in descending order of signal to noise ratios (SNRs).
14. The reception apparatus of claim 13 , wherein the interference removing is achieved by Minimum Mean Square Examination (MMSE) or Zero Forcing (ZF).
15. The reception apparatus of claim 13 , wherein a signal-to-noise ratio (SNR) criterion of each reception antenna, determined at the receiver at every retransmission, is used for selection of the retransmission ordering.
16. The reception apparatus of claim 15 , wherein a highest SNR of each reception antenna maximizes a determinant that derives a channel matrix after each retransmission.
17. The reception apparatus of claim 16 , wherein the channel matrix is adaptively changed by checking a channel every time there is a need for retransmission.
18. The reception apparatus of claim 16 , wherein the channel matrix is expressed as
H
M
×
N
=
(
h
11
h
12
⋯
h
1
N
h
21
h
22
⋮
⋮
⋱
⋮
h
M
1
…
…
h
M
N
)
.
19. A method for ordering retransmissions in a Multi-Input Multi-Output (MIMO) system using N×M antennas, the method comprising:
splitting, by a transmitter, a coded data stream into N sub-packets;
transmitting the N sub-packets from the transmitter to a receiver via N transmission antennas;
removing, at the receiver, interferences of the N sub-packets received via M reception antennas, and independently decoding the interference-removed sub packets;
receiving by the transmitter from the receiver, a negative acknowledgement (NACK) in response to errors included in the N sub-packets received by M reception antennas that have had their interferences removed and been independently decoded by the receiver;
arranging, by the transmitter, columns of a retransmission matrix based on an Alamouti space-time coding scheme in descending order of signal to noise ratios (SNRs); and
retransmitting from the transmitter to the receiver a retransmission sub-packet according to the arranged columns in response to the received NACK.
20. A reception method for retransmissions in a Multi-Input Multi-Output (MEMO) system using N×M antennas, the method comprising:
transmitting, by a receiver, one of an acknowledgement (ACK) and a negative acknowledgement (NACK) to a transmitter depending on errors included in one or more decoded sub-packets;
receiving, from the transmitter, a packet retransmitted in response to the NACK;
receiving N sub-packets split from a coded symbol stream separately by M reception antennas;
combining, by a pre-combiner, the packet retransmitted according to a retransmission ordering, with a previous defective packet on a symbol level;
removing, by a detector, interference of a signal received from the pre-combiner;
splitting, by the detector, the interference-removed signal into N transmission data sub-packets; and
outputting, by the detector, independently decoded sub-packet signals,
wherein the retransmission ordering comprises arranging columns of a retransmission matrix based on an Alamouti space-time coding scheme in descending order of signal to noise ratios (SNRs).Cited by (0)
No later patents cite this yet.
References (0)
No backward citations on record.